To verify that the observed differences between targeting vectors and MVNSe-LV were due to MV neutralizing antibodies in human plasma, we incubated CD20-LV, CD133-LV, CD133w/oLinker-LV and MVNSe-LV vectors in serial dilutions of complement inactivated α-MV antibody-negative human serum from non-vaccinated donors without previous MV infection. Here, PROM1 is linked to infection.